Muslim parents need to do more to protect their children from being groomed online by extremists, Home Secretary Theresa May has said.

Several young Islamic Brits have already slipped the net and headed out to the middle East to join Islamic State (IS).

Among those who have headed out to Syria are Cardiff brothers Nasser and Aseel Muthana as well as their friend Reyaad Khan.

But Conservative MP Mrs May - who was dealt a blow after having to drop new rules preventing universities and colleges to ban external extremist speakers - said the UK Government would continue to do all it could in the fight against terrorism.

However, she called on mothers and fathers to become more aware of what their children got up to online.

During a ministerial visit in the Welsh capital, she said: "I think that parents don't sometimes realise the impact of the internet and particularly social media.

"Sometimes they don't know what interactions their children are having and what is going on can be effectively unseen by parents.

"One of the messages that I want to give to parents is that if you are concerned they might be being radicalised or if they might be thinking of going to Syria to join terrorist groups please say something as soon possible."

Mrs May's comments came on the same day that five teenage girls said to have shown an interest in going to Syria were barred by a High Court judge from travelling abroad.

The two 15-year-olds and three 16-year-olds were made subject to a court order by Mr Justice Hayden - and are prevented from leaving the jurisdiction of England and Wales.

Mrs May said the threat the UK faced from terrorists was a real one - and also rebuffed suggestions the police were becoming "armed via the backdoor".

Earlier this week it was reported that armed police officers have been deployed at the Welsh Assembly's Senedd in Cardiff Bay

When quizzed on the matter, Mrs May said: "I'm very clear, the police are very clear, overall police officers do not want to be carrying guns. We are not in a position of wanting to arm police in England and Wales."

She added: "There are a number of police officers who are trained firearms officers who are deployed under certain circumstances.

"The threat level (to the UK) was raised last August to severe, a decision taken independently of ministers.

"That means that a terrorist attack is highly likely. That is the threat level against which we are all operating."

She also disputed recent claims by Labour that Wales could lose as many under 1,500 police officers if the Tories were to win the next UK election.

But during her visit to the Plough pub in the marginal constituency of Whitchurch, Mrs May insisted good policing was not just about the number of officers available.

"What is important is how you deploy and how you use the resources that you have," she said.

"It's not just about numbers of police officers. It's about what the police officers are doing."

She also defended the UK Government's decision to introduce elected Police and Crime Commissioners and the decision not to devolve policing to Wales.

She added: "I think we have a good model at the moment in terms of how things are operating."